High pressure nozzles are used in a variety of fields and for a variety of purposes. For example, high pressure nozzles are used to clear blockages within pipes, to wash debris out of pipes, and to polish the internal surfaces of pipes by forcing a nozzle attached to the end of a hose through the pipe. The pressure within such nozzle systems is relatively high, thereby applying significant forces to the internal orifices of the nozzle, which results in a limited nozzle life. Pressures of these types of nozzle systems are generally between 1500 and 3600 psi, but may be greater than 40,000 psi in some systems.
A number of different types of nozzles and nozzle assemblies are commercially available, each having advantages and disadvantages. One-piece nozzles are the most common type of nozzles. Typically made of stainless steel, these one-piece nozzles are generally the least expensive to manufacture. However, because the nozzle is provided as a single piece, the entire nozzle must be replaced once the high forces acting on the internal orifices have caused sufficient damage to effect the performance of the nozzle.
Other nozzles are designed having a body and an insert, the insert being threaded, press fit or mechanically attached to the body. The inserts are replaceable, and include the narrow orifice through which the water is forced to create an increase in pressure. This orifice is the part of the nozzle that wears out over time due to erosion from the water stream and particles within the water stream, corrosion, and rough handling. Thus, by providing the orifice in an insert of the nozzle, only a part of the nozzle must be replaced periodically.
High performing nozzles include inserts that have a tapered entrance opening which results in improved fluid flow and improved performance of the nozzle. These high performance nozzles do not present manufacturing difficulties when they are made of stainless steel because it is easily machined to accurate dimensions. In high pressure applications it is preferable to make the nozzle insert out of carbide because carbide is a harder material and offers greater resistance to the erosion caused by the high pressure flow. However, unlike stainless steel, carbide is extremely difficult to machine. Therefore, carbide nozzle inserts are currently cast to the desired shape, including a tapered entrance opening, to minimize the machining required. The orifice of the insert can be cast to size, or can be formed by using practices such as wire EDM. The outer surface of the cast fitting is sometimes ground for smoothness, or ground for an accurate press fit. The cost of manufacturing these fittings is high because each nozzle is cast individually.
Thus, the need exists for a high performance insert assembly that has an increased life span but is relatively easy and inexpensive to manufacture.